Antigenic proteins and vaccines containing them for prevention of coccidiosis caused by eimeria Eimeria necatrix and Eimeria tenella

Abstract

A purified antigenic protein has been obtained which is capable of inducing in a chicken an immune response conferring protection against infection by Eimeria necatrix or Eimeria tenella. The protein has a molecular weight of about 26,000 and is composed of two polypeptides joined by a disulfide bond. The two polypeptide subunits have molecular weights of about 18,000 and about 8,000, respectively. The gene encoding the protein has been sequenced and the amino acid sequence of the protein deduced therefrom. The protein and antigenic polypeptides having an amino acid sequence included within the protein may be incorporated into a vaccine for conferring upon a chicken active immunity against infection by E. necatrix or E. tenella.

What is claimed is: 
     
       1. A purified antigenic protein of Eimeria necatrix free of Eimeria necatrix sporozoites or sporocysts, which induces in a chicken an immune response conferring protection against infection of Eimeria tenella, the protein having a molecular weight of about 26,000 daltons and being composed of two polypeptides joined by a disulfide bond, one of the polypeptides being characterized by a molecular weight of about 18,000 daltons, by a blocked N-terminal amino acid not accessible to Edman degradation, and by the amino acid sequence set forth in FIG. 5, and the other of the polypeptides being characterized by a molecular weight of about 8,000 daltons and by the amino acid sequence set forth in FIG. 5.